改进型撞击流反应器流动特性研究

Research on flow characteristics of an improved impinging stream reactor

为研究入口动态变化流体流速的撞击流反应器流动特性,以空气和煤粉为工质,与标准工况撞击流进行对比分析,采用离散颗粒模型对新型撞击流反应器进行数值模拟。模拟结果表明:改进型撞击流流场同样分为入口区、撞击区、出口区和漩涡区,撞击面不再固定在反应器的几何中心,而是在一定范围内做反复振荡运动,左右振幅相差不大。在反应器中,其最大的湍流强度仍位于撞击区,以撞击面为分界点,气流入口速度大的一侧湍流强度要大于入口速度较小的一侧,其总的湍流强度也增大了,传热传质更激烈。改进型撞击流反应器的颗粒运动轨迹比传统撞击流要更长一些,混合更充分。

The flow characteristics of improved type impinging stream with inlet dynamic fluid velocity from an impinging stream reactor were studied. Compared with the impinging stream under standard working condition,the improved type impinging stream reactor taking air and pulverized coal as mediums is simulated using discrete particle model. The simulated results showed that the improved impinging stream flow field is also divided into the inlet area,the impact zone,the exit zone and the vortex area. The impinging surface is no longer fixed to the geometric center of the reactor,but repeats oscillation in a certain range,the difference between the left and right amplitude is very small. Besides,with the impact surface as a cut-off point,the turbulence intensity at the larger side of air inlet velocity is larger than that of the smaller side of the inlet velocity. As the total turbulence intensity is larger than that of the standard impinging stream reactor,heat and mass transfer is more intense. The particle motion trajectory of the improved impinging stream reactor is longer than that of the conventional impinging stream,and the mixing is more adequate.